Electric welding process.



E. KATZINGER. ELECTRIC WELDING PROOESS. APPLIUATION FILED un e, 1910.

1,664,338. Patented June 10,1913.

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EDWARD KATZINGER, 0F CHICAGO, ILLINOIS.

ELECTRIC WELDING- TBOCESS.

Specification of Letters fatent.

Patented J une 10, 193.

application med my s, 1am. seriai'no. esami.

To all whom t may concern.'

Be it kno-wn that I, EDWARD KATZINGER, 'a citizen of the United States, residing at yChicago, in the county'of -Cooli and State ofy Illinois, have invented certain new and useful Improvements in Electric l/Velding Proci esses, of which the following is a speciicaj the sheets which is the heavier one when;

tion.

This invention relates to processes of" ,tvfltha flattened protuberanoe or projection Welding by elect-rie currents, and has for its primary object to provide an improved spotl welding process by means of which two pieces of sheet metal can be easily, rapidly i and effectively united.

One of the objects is to provide an improved electric spot welding process for uniting two pieces of sheet metal which shall be peculiarly serviceable in welding a relatively heavy sheet or strap to a thinner one. l Other and further objects willappear in the specication and `be more specifically pointed out in the appended claims, reference being had to the accompanying drawings exemplifying the invention. ln the drawings-Figure l is an elevation,

parts being shown in section, of a pair of co operating dies by means of which a piece of sheet metal may be provided with protuberances according to the 'present inven- Fig. 2 is a view in elevation of two sheets superimposed one upon the other, one of said sheets being provided with attened protuberances constructed in accordance with the princi les of this invention. Fig. 3 is a top plan view of the upper sheet shown in Fig. 2. Fig. 4 isa View in elevation of cooperating electrodes with welded sheets therebetween, shown in section.

In well known processes of spot welding, it is customary in welding 'together a relatively thick sheet and a relatively thin sheet, to provide pointed protuberances on the thicker sheet, and after the thinner sheet has been placed in contact with the points of said protuberances, to make the Welds under pressure between oppositely disposed electrodes. In these processes, not only are the welds frequently imperfect, due t' the concentration of too large current on a small portion of the thinner sheet, with the consequent burning of the same, but the point of protuberance on the heavier sheet tends to indenty and at times passes entirely through the thinner Sheet, so that a soft metal .electrode pressed against the thinner sheet commonly becomes disfigured by indentations or cavities to such an extent that its serviceability becomes impaired. To avoid these diculties is one of the objects of this invention.

According. to the resent invention, one of they are lof different thickness is provided 2, which is preferably of uniform cross section throughout, and has a facet 3 formed on the outer end to adapt it to have a comparatively broad welding Contact with a second or thinner sheet 4:, as shown in Fig. 2. An efficient means for forming ythe protuberances 2 with flattened Vend faces 3 consists of coperating dies 5 and 6, one of said dies being provided-with a protuberance 7 and the other of said dies being provided with a rve'ld or socket .8. The relative proportions of said protuberan'ces and socket are such as to form Y.the protuberanees 2 when the dies 5 and 6 are brought together with .the sheet l interposed.. According to Figs. 2 and 3, the sheet l is provided with a .plurality of protuberances 2, 2., adapting the sheets to be welded together at these points., in Fig. 4, which illustrates the final step of the process, a pair of coperating electrodes 9, 10 are shown in positions above and below the sheets and 2, which4 positions they occupy after being pressed together on opposite sides of said sheets to effect the weld during the passage of a welding current, The welded portion is indicated in this figure by a vertical cross hatching.

By an inspection of Fig. 4, it vwill be noted that the electrode 10 which bears against the thinner sheet i is made considerably larger i in cross section than the cross sectional area` 0f the weld between the two sheets. By this means, the welding current as it passes into the thinner sheet 1s diffused radially in all directions so that `without impairing the Weld, `the possibility of burning the thinner sheet d is reduced to a minimumo What l claim isl. The process of electrically welding two sheets of metal which consists in stamping one of said sheets between coperating dies to form a plurality of uniform projecting portions with equal dat end facets, in a plying said facets to the other sheet andan 'otler through said rojections.

passing a welding current through said sheets and projections while pressing the sheets together.

2. The process of welding together two metal sheets, which consists in providing one of said sheets with protuberances havinveach the same cross-section throughout. an equal at end facets, in pressing the other sheet against said end facets, and finally in passing a welding current from one sheet to the other through said protuberances. j

The proce/ss of weldin together' two metal sheets of different thicknesses which consists in providing the thicker sheet with equal attened projections having substantially the same cross-sectional area, in pressing the thinner sheet against the atsurfaces of said projections, and nally in passa welding current-from one sheet to the two 4. The process o welding together `sheets of diierent thicknesses which .con-

thicker sheet with sists in providing the flattened protuberances all having substantially the same cross-sectional area in applying the thinner sheet tothe flattened protuberances, and in pressing saidsheets together between electrodes while passing a w'elding current through said electrodes and sheets, he electrode bearing against the thinner :sheet being of relatively largel area in comparison to the rotuberance to difuse the current throug the thinner sheet around said protuberance.

5. The process-of electrically spot weld-w Herent thicknesses metal sheets of di y which consists in forming the thicker sheets with projections of equal cross section, each having a iattened end, in placing the sheets one against the other with said projections spacing them apart, and in pressing the sheets together between electrodes while passing awelding current through said electrodes and sheets, the electrode bearing against the thinner sheet being of relatively large area in comparison to the cross-sectional area of thev protuberance to equalize the current density of the welding current through the thinner sheet around the protuberance.

6. The process of welding together tw'o metal sheets of dierent thicknesses which consists in forming the thicker sheet with rejections having substantially the same cross-sectional area and flattened tops of equal area, in pressing the gether between electrodes having a larger area than the cross-sectional area of the rojections, vand-in passing a welding current through said electrodes and sheets. v

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, on this 2nd day of May A. D. 1910.

. EDWARD KATZINGER.

Witnesses i W. CANTWELL, j A. O. Kniorrr.

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metal sheets tov 

